docs: def get_rna_leaves(graph) -> Iterable[BaseEntity]:
      """Iterate over all RNAs who have only one connection, that's a translation to its protein.
  
      :param pybel.BELGraph graph: A BEL graph
      """
      for node in get_nodes_by_function(graph, RNA):
          if graph.in_degree(node) != 0:
              continue
  
          if graph.out_degree(node) != 1:
              continue
  
          _, _, d = list(graph.out_edges(node, data=True))[0]
  
          if d[RELATION] == TRANSLATED_TO:
              yield node